GCSE Chemistry Edexcel 2027
Preparing for Pearson Edexcel GCSE Chemistry 2027? This exam rewards students who can do more than remember facts. If you can explain chemical ideas clearly, apply them to unfamiliar contexts, and handle calculations with confidence, you’ll pick up marks quickly across both papers. On this page you’ll find the full topic overview and practical, exam-focused advice to help you prepare.
Exam content
The Pearson Edexcel GCSE Chemistry 1CH0 specification for 2027 covers nine main topic areas:
Key concepts in chemistry provides many of the ideas and calculations used throughout the course. You need to understand atomic structure, isotopes and the development of the periodic table, including the work of Dmitri Mendeleev. You’ll also study electronic configurations and how these relate to an element’s position in the periodic table.
Bonding is a major part of this topic. You need to understand ionic, covalent and metallic bonding and use structure and bonding to explain properties such as melting point, conductivity and solubility. This includes simple molecular substances, giant ionic and covalent structures, metals, graphite, diamond, graphene and fullerenes.
Quantitative chemistry is also important. You’ll work with relative formula mass, percentage composition, empirical and molecular formulae, conservation of mass, reacting masses and concentrations in g dm⁻³. Topic 1 is assessed on both Paper 1 and Paper 2, so these ideas can appear throughout the course.
Higher Tier only
- Calculate relative atomic mass using isotope masses and abundances.
- Understand the mole and Avogadro constant.
- Calculate between mass, moles and numbers of particles.
- Identify the limiting reactant in a reaction.
- Deduce the stoichiometry of a reaction from masses of reactants and products.
This topic covers the particle model, changes of state and techniques for separating mixtures. You need to understand the arrangement, movement and energy of particles in solids, liquids and gases and explain what happens during melting, freezing, boiling, condensing and other changes of state.
You’ll also distinguish pure substances from mixtures and use melting-point data as evidence of purity. Separation techniques include filtration, crystallisation, simple distillation, fractional distillation and paper chromatography. Make sure you can choose an appropriate method for a mixture and explain why it works.
Chromatography questions can include interpreting chromatograms and calculating Rf values. You’ll also study how waste water, ground water and sea water can be treated to produce potable water.
Tier note
Pearson does not identify any content within this topic as Higher Tier only.
Chemical changes covers acids, alkalis, salts, precipitation and electrolysis. You need to understand the pH scale, indicators and the reactions of acids with metals, metal oxides, hydroxides and carbonates. You’ll also study neutralisation and methods for preparing soluble and insoluble salts.
Practical chemistry is important here. You need to understand salt preparation and acid-alkali titration, including the use of burettes, pipettes and suitable indicators. You should also know the main solubility rules and use them to predict whether a precipitate will form when solutions are mixed.
Electrolysis includes molten and aqueous ionic compounds. Make sure you can predict the products formed at each electrode and explain how ions move and gain or lose electrons.
Higher Tier only
- Relate hydrogen and hydroxide ion concentrations to pH.
- Understand that a tenfold change in hydrogen ion concentration corresponds to a change of one pH unit.
- Distinguish between concentrated and dilute solutions and between strong and weak acids.
- Explain strong and weak acids in terms of the extent to which they dissociate into ions.
- Write half-equations for reactions at electrodes.
- Explain oxidation and reduction in terms of electron transfer.
This topic links the reactivity of metals to their extraction and use. You need to understand the reactivity series, displacement reactions and oxidation and reduction. Metals below carbon can usually be extracted from their ores by reduction with carbon, while more reactive metals require electrolysis.
You’ll also consider alternative methods of obtaining metals, recycling and life-cycle assessments. These questions often ask you to compare processes using environmental, economic and practical information rather than simply recalling a method.
The second part of the topic covers reversible reactions and dynamic equilibrium. You need to understand the Haber process and its conditions, as well as how changes in reaction conditions can affect an equilibrium.
Higher Tier only
- Explain displacement reactions as redox reactions involving electron transfer.
- Evaluate biological methods of extracting metals, including bacterial extraction and phytoextraction.
- Predict how changes in temperature, pressure and concentration affect the position of a dynamic equilibrium.
Separate chemistry 1 contains additional content studied in GCSE Chemistry but not Combined Science. It begins with transition metals, alloys and corrosion. You need to understand typical properties of transition metals, why metals corrode and how rusting can be prevented using barriers, sacrificial protection and electroplating. You’ll also study alloys and how their structures affect their properties.
Quantitative analysis includes concentration, titration, percentage yield and atom economy. The accurate acid-alkali titration is one of the mandatory core practicals. You’ll also consider how chemists choose between different reaction pathways and use quantitative information to evaluate chemical processes.
The topic continues with gases, industrial equilibria, fertilisers, chemical cells and hydrogen-oxygen fuel cells. You need to understand how industrial conditions are chosen and evaluate the advantages and disadvantages of different chemical technologies.
Higher Tier only
- Calculate concentrations in mol dm⁻³ and convert between mol dm⁻³ and g dm⁻³.
- Use titration results to calculate unknown concentrations or volumes.
- Choose between reaction pathways using information such as yield, atom economy, rate and equilibrium position.
- Use molar gas volume in calculations involving masses and gas volumes.
- Use Avogadro’s law to calculate reacting gas volumes.
- Predict how conditions affect the rate at which equilibrium is reached.
- Explain how industrial conditions are chosen as a compromise between yield, rate, energy use, pressure, catalyst use and cost.
This topic focuses on Groups 1, 7 and 0 of the periodic table. For Group 1, you need to know the properties and reactions of the alkali metals and explain how their reactivity changes down the group using electronic configurations.
For Group 7, you’ll study the halogens, including their colours and physical states, reactions with metals and hydrogen, and displacement reactions. Make sure you can use patterns to predict the properties and reactions of other halogens.
Group 0 covers the noble gases. You need to explain why they are chemically inert using their electronic configurations and understand how properties such as inertness, low density and non-flammability make them useful.
Higher Tier only
- Explain halogen displacement reactions as redox reactions in terms of electron gain and loss, identifying which substances are oxidised and reduced.
Rates of reaction covers how quickly reactions happen and the factors that affect their rate. You need to understand collision theory and explain how temperature, concentration, pressure and surface area affect the frequency or energy of successful collisions.
You’ll also study catalysts and activation energy, interpret rate graphs and suggest practical methods for measuring reaction rates. The rates of reaction investigation is one of the mandatory core practicals, so be prepared to interpret methods, results and sources of error.
Energy changes include exothermic and endothermic reactions, bond breaking and bond making, activation energy and reaction profiles. Make sure you can connect changes in temperature to the energy transferred during a reaction.
Higher Tier only
- Calculate the overall energy change of a reaction using bond energies.
This topic covers hydrocarbons, fuels, the atmosphere and climate change. You need to understand crude oil as a finite mixture of hydrocarbons and explain how fractional distillation separates it into useful fractions with different boiling points and properties.
You’ll study homologous series, combustion and cracking. Complete combustion produces carbon dioxide and water, while incomplete combustion can produce carbon monoxide and carbon. Other pollutants from fuels include sulfur dioxide and nitrogen oxides, so make sure you understand their environmental and health effects. Hydrogen is also considered as an alternative vehicle fuel.
Earth science covers the development and composition of the atmosphere, the greenhouse effect and evidence linking human activity to climate change. You should be able to evaluate evidence, explain possible consequences of rising greenhouse gas concentrations and consider ways these effects could be reduced.
Tier note
Pearson does not identify any content within this topic as Higher Tier only.
Separate chemistry 2 contains several additional areas studied only in standalone GCSE Chemistry. Qualitative analysis includes flame tests, sodium hydroxide tests and chemical tests for ammonium, carbonate, sulfate and halide ions. You’ll also study instrumental analysis and interpret flame photometry data.
Organic chemistry includes alkanes and alkenes, their structures and reactions and using bromine water to test for unsaturation. You’ll also study addition polymerisation and the structures, properties and uses of common polymers, as well as issues surrounding polymer disposal and recycling.
The topic continues with alcohols and carboxylic acids, including their functional groups and reactions. You’ll investigate combustion of alcohols in a mandatory core practical. Natural polymers and different types of materials, including polymers, ceramics, composites and nanoparticles, are also included.
Higher Tier only
- Explain condensation polymerisation in the formation of polyesters, including the formation of ester links and water.
What to expect in the GCSE Chemistry exam 1CH0
Pearson Edexcel GCSE Chemistry is assessed through two written papers. Paper 1 assesses Topics 1–5, while Paper 2 assesses Topic 1 and Topics 6–9, so Topic 1 can appear on both papers. Each paper is 1 hour 45 minutes, worth 100 marks and accounts for 50% of the qualification. Calculators may be used in both papers.
Edexcel papers often build questions in stages. You might begin with a short recall question, then move into a calculation, then finish with an extended response. The best strategy is to treat each part as a mini task. Secure the early marks quickly, then slow down for the longer explanation and write it as a clear chain of reasoning.
Edexcel places strong emphasis on practical understanding through written questions. Even though there is no separate practical exam, you are expected to understand practical techniques and how to evaluate methods. When you see a method or results table, immediately identify the independent variable, dependent variable, and control variables. Then add reliability improvements like repeats, improved measurement precision, and controlling temperature. These points are predictable, and they score consistently.
Finally, if you are doing Higher Tier, train yourself to write linked answers. Many of the top-grade marks come from connecting ideas across topics, for example bonding and properties, or equilibria and industrial conditions. Practise with past-paper questions, learn your calculation routines, and always check units and rounding. In the exam, keep your answers concise but complete, show working clearly for calculations, and do not waste time rewriting the question. Write what earns marks.
